Pump and method of silencing and operating pumps



March 30, 1937. 7 E K 2,075,017

PUMP AND METHOD OF SILENCING AND OPERATING'PUMPS Filed April 27, 1932 v3 Sheets-Sheet 1 amt/WM March 30, 1937. E, BENEDEK 2,075,011 A March3.0, 1937. E. BEN EDEK 2,075,017

PUMP AND METHOD OF SILENCING AND OPERATING PUMPS Filed April 27, 1932 3Sheets-Sheet 3 Patented Mar. 1937 RATENT OFFICE PUMP AND METHOD orSILENCING AND OPERATING PUMPS Elek Benedek. Mount Gilead, OhioApplication April 27, 1932, Serial No: 607,697 Claims. ((-31; 103-161)This invention relates to variable displace- --Fig. 8 is averticalsectional view taken on a ment hydraulic pumps or motors of therotary 'radial piston type. i p

Heretofore, in this type of pumps, high emciencies and quiet operationat high pressure delivery have been prevented to a great extent byunsatisfactory valving relation between the valve pintle ports and thecooperating cylinder ports. It is one of the principal objects of thepresent invention to increase the 'emciency and render more quiet pumpsof this type operating at high pressures by proper pre-compression andpre-expension oi the operating fluid preparatory to, its communicationwith the respective pintle valve ports.

A correlative object is to maintain a more nearly constant degree ofpre-compression and preexpanslon oi the fluid throughout each intervalof such conditions and to immediately utilize the energy thus stored forreducing noise and eircessive hydrostatic unbalances.

Another object is to. eliminate excessive peaks of pre-cornpressionpressures and of negative pressures. a

A more specific object is to control the degree of pre-compression andpre-expansion of the fluid at the higher pressures in a predeterminedproportional relationship to the pressure delivery of the pump.

Another object is tdzprovide a new and improved piston actuatingassemblage and mounting whereby a high emciency of transmission of ap-'plied forces may be obtained.

Other objects and advantages will become ap- 7 parent from the followingspecification wherein reference is made to the drawings in which 5? Fig.1 is a verticalcross sectional View througha pump or motor embodying theprinciples of the present invention;

Fig. 2 is a horizontal sectional view-oi the pump or motor and is takenon a plane indicated by the line 2--? of Fig. 1;

Figs. 3 and i are cross'sectional views of one end of the pump casingshowing the *manner of indicated by the line ii$ of Fig. 5

Fig. '7 is a side elevation, partly in section, of the reactor-ice rotorof the pump and motor illustrated. in Fig. 1'; v

; extending lugs it which plane indicated by the line 8-8 of Fig. 7 andFig. 9 is a top plan view 01' the reactance rotor illustrated in Figs. 7and 8.

For the purposes of illustration, the present invention will bedescribed as a pump, its operation as a motor being readily apparentfrom such description, and it is to be understood that in thespecification and claims, the structure recited is meant to be either apump or a motor, though referred to only as a p. correspondingly, thevalve pintle ports are referred to as suction and pressure, only fordistinguishing the same from each other more readily, regardless of thefact that both are pressure ports when the structureis operated as amotor.

The pumping mechanism is enclosed in ahousing id,'closed at the-ends byrigid end covers ii and 52 respectively, the cover it being disposed atI the driving shaft end of the pump.

of the sets being snugly received in internal annular recesses in therespective covers 6 i and E2.

The end cover if. is provided with a heavy annular hub portion i8 havinga bore extending axially of the rotor id and tapered radially inwardlyfrom its inner toward its outer end for receiving and mounting thecomplementary tapered shank i'i oi a valve pintle it. A portion 23 ofthe pintie it extends beyond the hub portion it for recei apintleadjustlng wheel 22-.

The ndjustmentwheel 22 is secured on the pro-.

trudinr. end 28 and locked thereto by a'key 26 for rotating the pintie.In order to draw the pintle shank y into the bore of the hub is whilerendering the plntie radially rotatable, the wheel 22 is provided withan annular radial bearing shoulder which abuts the outer race 02a set ofball bearings 2i, the inner race of these bearings engaging acompiementaryradial annular hear-1 ing shoulder on the hub l8. Asuitable nut 25 and washerfid are secured on the outer'end of the vportion 253' of the pintle and by reactance on the wheel Eddraws thepintle shank outwardly and snugly in the bore of the hub i8. Thehearings 29 thus transmit this thrust to the hub while prewheel 221sprovided thv a plurality of radially are received within venting bindingof the wheel thereagainst. The

notches 28 in an annular locksleeve 29 which 'is screw threaded onto theexterior of the hub l8 for holding the wheel 22 and'consequently the ipintle in predetermined rotated positions.

The hub I8 is provided with axially spaced annular recesses l9 and 20which communicate with the usual longitudinal passages in the valvepintle and, in turn, communicate with the main fluid lines of the pumprespectively.

The rotor l4 and pintle |6 are coaxial, the rotor being provided withthe usual pintle bore into which from one end the pintle l6 protrudesand is snugly received. The pintle terminates in spaced relation to theopposite end of the rotor bore. At the said opposite end, a main driveshaft 30 is provided, this shaft being secured for rotation with therotor through a suitable key 3| and drawn firmly in place by a lock nut32 so that the drive shaft and barrel form sub.- stantially a unitarystructure The drive shaft terminates in spaced relation to the free endof the pintle I6 and is in sealed relation to the rotor bore wall inwhich it is received, so that the pintle bore is, in effect, dead end.The end cover I carries a hubportion 33 having a bore through which theshaft 30 protrudes, the bore in the hub 33 being counterbored to receivesuitable packing washers 34 which are secured in place by the cap 35.

Mounted and reciprocable in the radial cylinders l5 of the rotor arerespective radial pistons 36, the outermost ends of which are slightlyenlarged to provide head portions carrying thrust pins 31 through themedium of which the pistons are reciprocated. The head portion of eachpiston is provided with a bore disposed at degrees to the piston axisand extending fore and aft in the direction of travel. The pins 31 aresnugly received therein. and secured in place by suitable set screws 38.For actuating the piston through the media of the pins, a reactancerotor or other suitable reactance means 39 is provided.

The reactance rotor is provided with a plurality of chordal bores 40,one for each piston, these bores extending 90 degrees to the pistonaxis. The bores 40 are preferably of suflicient length so that eachintersects those adjacent at the ends, as well as extend at the endsthrough the circumferential wall of the secondary rotor 39 so as topermit ready insertion of the pins 31.

In order to mount the reactance rotor for rotation, a reactance housing43, having inwardly projecting annular bearing elements 42, is mountedwithin the casing portion Ill. The bearing elements 42 are provided withinternal annular shoulders on which are received ball bearings 4|, oneset at each end of the reactance rotor'housing. Annular flangedcooperating bearing ele-' ments 46 are secured to the rotor 39 throughthe medium of bolts 41, the annular flanged portion of the members 46cooperating with the bearings 4| for rotatably supporting the rotor 39in the housing 43 and resisting axial displacement thereof.

It should be noted in connection with the reactance rotorthat itshousing 43 is shiftable for varying the effective. stroke of the pistonsand. consequently the volumetric and pressure delivery of the-pump. Forshifting the secondary rotor 39, its housing 43 is provided with rods 44and 45 extending through the suitable bores inthe wall of the casingportion I0. Likewise, as better 11-.

surfaces. These surfaces are cooperable with complementary flat bearingsurfaces in the housing portion Ill for maintaining the housing 43 andthe reactance rotor with their common axis parallel to the axis of theprimary rotor |4 while permitting shifting thereof to render the rotorsl4 and 39 coaxial or to dispose their axes parallel and offset from eachother.

As' above mentioned the valve pintle |6 isreceived in the bore oftherotor M with a snug fit for valving cooperation therewith, and isprovided with valve ports 50 and 5| which are spaced diametricallyopposite each other and positioned longitudinally of the pintle to bealigned successively with discharge ports communicating the cylinders |5with the bore of the primary rotor |4. Theports 50 and 5| areseparatedby diametrically opposite bridge portions 54 and ,55 whichextend circumferentially a distance considerably greater than thedischarge ports of the cylinders l5 so that, upon rotation of theprimary rotor with respect to the pintle for positioning each cylinderdischarge port successively in cornmunication with the ports 50 and 5|,each cylinder port successively is completely blocked by the bridgesduring part of its passage thereover. In the illustrative example, theports 59 and 5| are suction and pressure ports respectively. The ports,in turn, are in communication with the usual longitudinally extendingpintle passages 49 and 48 respectively. As better illustrated in Figs. 3and 4, the passages 48 and 49 communicate respectively with the passages20 and IS in the hub I8 of the end cover I2. The passages Hi and 20, intum, communicate respectively with the radial passages 53 and 52respectively in the hub |8 and through the passages 53 and 52 to theusual ing the round chordal bores 40 and round pins 31, however, theentire surfaces of each pin and the bore wall associated therewith isnot subjected to the full pressure and therefore the film of oil may beretained within the bore and around the pins with the possible exceptionof a relatively small surface under direct heavy pressure contact. Thisfilm is thus readily available so that when the pressure is relieved inthe slightest, as when the opposite stroke of the piston is begun, thisfilm may quickly envelope the pin and immediately relubricate pin andbore contact surfaces. Furthermore, the fllm of lubricant tends toremain even on the contact surfaces thus permitting the pins 31 to shiftaxially in the bores 40 so as to compensate for the lead and lag intangential travel'of the pistons relative to the reactance due toeccentricity of the rotors. Suitable oval radial passages 65 areprovided in the reactance rotor for accommodating the head portions ofthe pistons as they shift to and fro in the direction of travel duringthis compensating action. I

It is apparent that with this construction, especially when a long.stroke, small diameter piston is used, extremely great: pressures can bedeveloped. Here it should be emphasized that the 'pump is. primarily forvery high pressures and that its delivery is controlled by changing theeccentricity of the reactance rotor 39 relative to the primary rotor M.The eccentricity results in reciprocgjzion of each piston in onedirection throughout 180 degrees of angular travel of the rotor and inthe opposite direction throughout the remaining 180 degrees of angulartravel. In order to utilize the full efliciency of the pump and toprevent discharging of the fluid under pressure from any cylinder intothe suction port of the pintle, and to prevent relieving the suction inany cylinder by communication thereof with the high pressure port of thepintle, the bridges 54 and 55 of the pintle must extend a materialdistance circumferentially of the pintle. Necessarily, therefore, with arotatingreactance, and for some stationary reactances, the pistonscannot complete either stroke while their cylinders are in communicationwith either of the 0 ports 58 and ti.

Referring to Fig. 1, and assuming, for example, the direction ofrotation of the pump is clockwise, the port 5d the intake or suctionport and the port 58 is the discharge or pressure port, it

5 will .be seen that the changes in the direction of reciprocation foreach piston occur when the piston axis is disposed horizontally. Thebridges 5d and 55, however, are aligned with the cylinder ports at thesetimes, respectively. Assuming that 0 the rotor housing 43 has beenshifted to the right, then, when a piston is disposed horizontally atthe right, it is at dead center, having completed its suction stroke andnot yet having-begun its pressure stroke. Since the bridges necessarily5 extend circumferentially of the pintle adistance greater than thecylinder ports so as to prevent undue fluid slip and passage of fluidfrom the pintle pressure port through the cylinder and directly into thepintle suction port, the bridges necessarily block and seal eachcylinder port, in turn, as the port approaches'and recedes fromhorizontal or dead center position. Consequently, the cylinder ports aresealed and the fluid drawn into the cylinder is trapped. In highpressure pumps requiring wider bridges for elimination of slip andlay-pass, the interval and travel during which thepiston is so sealedisgreatly increased. If the piston continues on the suction stroke afterthe cylinder port is sealed by a bridge, energy is u expended increating useless andlietrlmental sub-atmospheric pressure in thecylinder. Upon continued rotation, the piston returns on the pressurestroke, the cylinder remaining sealed.

I Thereupon, the piston moves part way entirely unopposed by fluid andstrikes the fluid with a sudden sharp impact resulting in vibration,noise, and stresses of the working parts. Having struck the fluid,compression begins and continues for an interval while the cylinderremains sealed. Since the volume of the small quantity of fluid in. thecylinder cannot be reduced appreciably by compression, an extremelyexcessive pressure is immediately created in the cylinder and morenoise, stressv and vibration results, often locking the rotor anddamaging the pump parts. Uponcontinuance of this stroke, the cylinderport communicates with the pintle pressure port in which the pressure isfar below that instantaneous excessive pressure in the cylinder. Hereagain, a detonation results which causes a surge in'the deliverypressure of the pump and additional noise and vibration. This almostinstantaneous release also reduces the resistance to rotor rot'ationsuddenly and a surge in angular velocity 5 of the. rotor results. It thepump should be so timed that the pressure in a cylinder on compressionis less than'the pintle port pressure at the instant of communication,obviously a surge'from the pintle port into the cylinder would result.

Again, contining this stroke as the cylinderport approaches the oppositebridge, some fluid remains in the cylinder after the port is againblocked thereby. excessive compressive pressure is developed andcontinues until the piston axis is horizontal with the piston disposedat the left in Fig. 1. Thereupon begins the suction stroke, but since nofluid can enter the cylinder port, due to the bridge, 55, considerablenegative pressure is developed in the cylinder. As soon as the cylinderport communicates with the port 50, a negative pressure compartment isexposed to the fluid and thereis an instantaneous 'inrush of fluidcausing additional noise and vibration.

The .above conditions, though not so pronounced in low pressure pumps,are so exag-' Thereupon, another sudden gerated in high pressure pumpsas to become almost fatal defects. To reduce these undesirable effectssubstantially to the point of complete elimination is the principalobject of the present iii-- .be communicated with the pintle pressureport and with the pintle suction port only when the fluid pressures inthe cylinders are equal to the fluid pressure in the particular pintleport with which to be communicated and. that during the passage of eachcylinder across the intervening bridges, no excessive pressures, eitherpositive or negative, are developed. All of these results ma b realizedand silent, smooth operation afforded by proper, tore-compression andpre-expansion of the operating fluid. This is accomplished byadvancement of the angular position of the pintle in the direction ofrotor rotation from its normal position and by the provision of fluidcompression chambers. v

Referring to Figs. 1 and 2, the fluid compression chambers foraccomplishing more uniform pre-compression and pre-expansion pressuresare illustrated. These chambers may comprise large capacity fluid tightbores 5B and as preferably formed directly in the valve pintle it andextending longitudinally thereof The chambers are provided with ports 5%and El respectively which open onto the bridge surfaces 55 and 5trespectively. Since the chambers may be the same in form and function,the chamber 59 only will be specifically referred to.

The port bl which is the only opening into the chamberts is preferablypositioned on the bridge Tracing the operation of the chambers, it isapparent that slightly before any cylinder reaches the horizontalposition, its port comes into communication with one of the compressionchambers 59 while yetin communication with the pintle suction port II.when the piston axis is horizontal and to the right in Fig. 1, thecylinder port is in communication only with chamber 59 and is blockedfrom communication with ports 5|I'and 5| by the bridge portion 54.Consequently,

as the piston starts upon its compression stroke,

the fluid is trapped in the cylinder and chamber 59 and ispre-compressed in the cylinder and in the compression chamber 59. Thechamber 59 is of capacity such that a sufliciently large amount of fluidcan be compressed thereinto without a disproportional increase in thefiuid pressure, to accommodate that discharged by the cylinder. beforeit communicates with port 5|. If the chamber were of toolimited'capacity, substantially the only reduction in volume of fluidthat could occur would be that due to compression of the fluid directlyin the cylinder. The latter is so limited that an excessive pressurepeak would immedi-- able uniformity of higher pressure to a pressuresubstantially equal to that in the port 5|. Im-

mediately upon communication of the cylinder port with the port 5| ofthe pintle, the fluid is discharged at-this pressure without a suddendrop in the cylinder pressure which would result upon release of aslight volume. of fluid at excessive compression. During initialcommunication, some re-expansion of fluid in the chamber 59 maintains aflow therefrom whereupon it is in condition for cooperation with thenext cylinder. The pressure in the chamber 59 may become slightly abovethat of line delivery but this is immediately relieved andall of itsenergy utilized.

Continuing the movement in a clockwise direction, the piston movesupwardly toward the horizontal position at the left of the pump tocomplete its compression stroke and begin its suction stroke. The fluidin the chamber 58 is at ordinary atmospheric pressure, consequently ittends to reduce the pressure in the cylinder as the cylindercommunicates therewith. However, the cylinder port communicates with thechamber while remaining in communication with the port 5|. Consequently,some fluid is compressed a given amount in the chamber 58. As thecylinder continues travelingupwardly and begins its suction stroke, thisfluid re-expands concurrcntly and is passed back into the cylinder so asto fill the portion of the cylinder in advance of the piston andmaintain it at substantially atmospheric pressure, the same as port 50,at the instant that it communicates with the port 50. Therefore, thenoise due to a sudden release of highly compressed fluid and due to asudden rush of fluid into a comparatively great negative pressure in acylinder will be eliminated.

From the foregoing it can readily be seen that for a given operatingpressure of the pump,

pounding, vibration and noise can be so greatly reduced as to beunnoticeable. However, as the pressure at which the pump is operating isincreased, the degree of pre-expansion and precompression mustnecessarily be increased for maintaining this balance, otherwise noiseand vibration will again result. The operating fluid pressure of thepump is increased and decreased solely by shifting the secondaryrelctance through the medium of the rods 44 and 45. The pre-compressionfor effecting silent operation, however, is provided by rotating the.pintle through different angular distances, the pintle being advanced inthe direction of rotation for" silencing operation at higher pressuresand returned toward normal operating position for silencingoperation atlower pressures. For example, as the pi'ntle is advanced in thedirection of rotation, due to the accelerated rate with which the pistonmoves inwardly after it passes dead center for a given angular rotationof the piston, a greater movement of the piston is occasioned during theinterval in which the piston cylinder is blocked by its cooperatingpintle bridge. Thus necessarily a -higher pre-compression results. Thesame is true upon expansion on the suction stroke. The chambers 58 and59 therefore must be of suflicient capacity for receiving this greateramount of fluid at the higher compression and longer portion of stroketo prevent excessive pressure peaks during these relations. Here, again,

' at the higher pressures, if the pressure .in the.

cylinder-is equal substantially to that in the port with which it is tobe communicated, no pounding and vibration will result nor will there beany sudden release of pressure which would tend to make the rotorincrease in velocity. While this arrangement is satisfactory for mostinstances, it often happens that the particular apparatus being drivenby the pump or motor is blocked or jammed with the result that the flowin the forward line 64 is suddenly decreased accompanied by a suddenincrease in pressure. If the pump continued to operate with a givensetting of the pintle at this higher pressure or lower pressure,

as the case may be, excessive pounding and noise is fixed for rotationwith the pintle 23, a suitable I notch 6| being provided in the hubportion l8 to permit limited movement of the head of the key 60. At oneend of the key 59 in the direction of advance movement of the pintle,there is provided a spring 62 of predetermined strength which abuts thecorresponding'end of the key and urges it in the opposite direction tonormal position.

At the opposite end, a plunger 63 operating in a .suitable fluidpressure bore is provided, the

plunger bore being communicated with the working fluid of the pumpthrough the line 64. Thus as the pressure in the line 64', increases itmay overcome the force of the spring and shift the key 60 in thedirection for rotating the pintle I5 through the medium of the endportion 23 to advance position. When, however, the pressure is reducedin the line 64, the spring will turn the key and pintle in the oppositedirection. The limits within which the pintle can be rotated may befixed by the side walls of the notch 6|. The elements are so arrangedthat when low line pressure is provided, the pintle will lie in itstheoretical position in which, when the dead center position of eachpiston is reached, its cylinder port will occupy the center of itscooperating bridge. However, as the pressure in the working 1 line 64increases, the advancement of the pintle will be increased also so thatrotation of the pintle will be suflicient to pre-compress and pre- 5expand the fluid to a pressure substantially the' being all that isrequired. This maximum is dey termined by the compressibility of theparticular working fluid used, however. Thus not onlyis the mechanismsilenced, but sudden fluctuations of pressure of delivery areeliminated. I

Having thus described my invention, I claim:

1. The combination with a hydraulic rotary radial piston type pump, ormotor, including a rotatably adjustable valve pintle having fluid ports,a rotor having radial cylinders with portsv cooperable successively withthe pintle' ports, piston assemblages respective to the cylinders,adjustable reactance means cooper-able with the piston assemblages inreciprocating the same,

and'means for adjusting'th'e reactance means to different positions forvarying the delivery fluid' ofthe pump, of means responsive to changesin the delivery pressure of thepump for rotatably adjusting the pintleto different angular positions for silencing operation of the pump.

, 2. The combination with a hydraulic'rotary radial piston type pump, ormotor, including a rotatably adjustable valve pintle having fluid ports,a rotor having radial cylinders with ports cooperable successively withthe pintle ports, piston assemblages respective to the cylinders,reactance means cooperable with the piston assemblages for reciprocatingthe same, means for adjusting the reactanee means to difierentposi- 40tions for varying the delivery of the pump, or" means operated 'by thefluid pressure delivered by the pump to adjust the angular position oi?the pintle in the direction of rotation of the rotor in a predeterminedproportional relationship to increases in the fluid delivery pressure ofthe pump to thereby silence the operation of the pump at f the difierentdelivery pressures. I 3. In a hydraulic rotary radial piston pump ormotor including a rotor having circumferentially 5d spaced radialcylinders and piston assemblages respective thereto, and portsrespective to said cylinders, reactance means cooperable with saidpiston: assemblages. to reciprocate the same, a valve pintle in valvingrelation to the rotor and having a suction port and a pressure port co.-

operable successively with each cylinder port as the rotor rotatesbridges intermediate the pintle ports for blocking each cylinder portwhen such cylinder port is aligned therewith, whereby fluid so istemporarily entrapped in the particular aligned cylinder, a fluid tightchamber having a port opening onto one, of said bridges forcommunication with the cylinder ports when aligned with said bridge,said chamber being otherwise sealed and filled with operating fluid, andhaving suflicient fluid-capacity to temporarily receive from' thecylinder and accommodate without an excessive increase in pressure aportion of the fluid trapped in the cylinder by virtue of compression ofthe fluid filling said chamber to thereby reduce I pintlereceived in therotor in valving relation and having a suction port and a pressure port,said pintle ports bein'g'successively cooperable with each cylinderport, bridges intermediate the pintle ports for blocking each cylinderport when aligned therewith, reactance means for the pistons positionedrelative to the pintle to drive the piston'assemblages to the respectiveends oi their strokes while their associated cylinder ports are blockedfrom communication with the pintle ports by said bridges respectively,said pump hav-- ing fluid tight chambers with ports respective to saidbridges and opening thereonto ror com munication with the cylinders whenthe pistons thereof are at the said ends of their strokes,- wherebypre-co'mpression and pre-expan'sion of fluid in the cylinders niay beefiected without excessive instantaneous increases ,inpressure, byexpansion-and compression of the fluid in said chambers, and saidchambers being continuously filled with operating fluid, whereby theinstantaneous flowthereinto, and therefrom is equal and reversible;

5. In a hydraulic rotary,-'radial piston pump or motor including a valvepintle having 'a pressure port and a suction port, a rotor having radialcylinders with ports cooperable successively with the pintle ports,pintle bridges between the pintle ports, piston assemblages respectiveto the cylinders, reactance means cooperable' with the pistonassemblages for driving them to the ends of their strokes andintoalignment with the respective bridges, means mounting said pintle forlimited rotation to'diflerent adjusted positions,

means cooperable with the pintle and cylinder ports for relievingexcessive pre-compression and relation to the cylinder ports at the endsof the I 4 piston strokes of the associated pistons of said cylinders inthe various adjusted positions of the pintle and thereby preventreversalof any piston stroke at an instant while its cylinder port is'incommunication with a pintle port.

6. In a rotary radial piston pump including a rotor having radialcylinders, piston assemblages and cylinder ports respective to thecylinders,

reactance means cooperable with said piston assemblages forreciprocating the assemblages, a valve pintle extending within the rotorand having a suction port and a pressure port successively cooperablewith each cylinder port, bridges intermediate the pintle ports forpreventing concurrent communication of any cylinder with both pintleports, whereby each cylinder port is blocked when aligned with thebridges and fluid is trapped in the cylinder, and a fluid tight chamheropening onto one of said bridges for com,-

' munication with each cylinder port when aligned therewith, saidchamber being filled with fluid cylinders with portscooperable'successively with tile pintle ports, pistonassemblagesrespective to and having suflicient fluid capacity to receivea the cylinders, reactance means cooperable with the piston assemblagesfor reciprocating the same consequent upon rotation of the rotor,bridges on said pintle intermediate the ports thereof, fluid tightcompression chambers having ports opening onto said bridges forcooperation successively with the cylinder ports, said chamber portsterminating circumferentially of the pintle a suflicommunicated withthepintle ports.

8. In a hydraulic rotary, radial piston pump or motor including a. valvepintle having a suction port and a pressure'port, a rotorhaving radialcylinders with ports cooperable successively with the pintle ports,piston assemblages respective to the cylinders, reactance meanscooperable with on said pintle intermediate the ports thereof,

fluid tight compression chambers having ports opening'onto said bridgesfor cooperation successively with the cylinder ports, said bridges.

extending circumferentially of the pintle a distarice suflicient toprevent concurrent communication of .any cylinder port with both pintleports, and said chamberports extending circumferentially of the pintlebridge a suflicient distance to communicate with the cylinder portcooperating with the bridge only, while the cylinder port isuncommunicated with a port of the pintle.

9. In a hydraulic rotary; radial piston pump or motor. including a valvepintle having a suction port and a pressure port, a rotor havingradialcylinders with'p'orts cooperable successively with the pintle ports,piston, assemblages respectiveto the cylinders, reactance meanscooperable with the piston assemblages for reciprocating the sameconsequent upon rotation of the rotor, bridges on mun-icate with thecylinder port cooperating with the bridge while the cylinder port isuncommunicated from the pressure port of the pintle, and means forrotating the pintle in the direction of rotation of the rotor forincreasing the degree of pre-compresslon of the fluid in said chamberpreparatory to communic'ationoi'the cylinder port and pintle pressureports. 7

' 10. In a rotary radial piston and cylinderpump, a valve pintle havinga suction port and a pres sure port, a rotor having a cylinder and acylinder port successively cooperable with said ports as the rotorrotates,,a piston reciprocable in the cylinder, reactance meanscooperable with the piston for reciprocating the same, a bridge on thepintle between the pintle ports having a valve continuously filled withthe operating fluid of the pump, said chamber being sealed except forsaid port and of adequate fluid capacity for receiving and accommodatinga predetermined quantity of fluid fromthe cylinder by compressivereduction of the volume of the fluid in they chamber during saidcommunication withsaid cylinder port and ,for redelivering the fluid soreceived through said chamber port by expansion of the fluid whenthefluid pressure thereon from the cylinder is relieved.

11. The combination with a fluid pressure pump or motor including-acasing, a rotatably adjustable valve having fluid ports, a rotorrelatively rotatable with respect to the valve and having acylinder, apiston in the cylinder, adjustable reactance means. for reciprocatingthe pistons, and means for adjusting the reactance means for varying thedelivery of the pump, of means responsive to changes in the operatingfluid pres-7 sure for rotatably adjusting the valve, and meansassociated with the valveand cooperable with the cylinder in all of theadjusted positions of the valve for effecting pre-compression' andpre-expansion of the operating fluid in the cylinder for reducing thenoise incident to'operation of the pump or motor by synchronizingthe'operating pressure with the pressure of the working fluid of the.cylinder.

12, In a fluid pressure pump or motor, a casing, a rotary barrel havinga cylinder, said cylinder having a port, a piston in the cylinder,adjustable reactance means to reciprocate the piston, means to adjustthe reactance means for varying the pressive reduction and expansion ofthe volume of the fluid in the chamber during communication of thecylinder and chamber, said chamber redelivering the fluid by expansionthereof when the chamber is relieved from the fluid pressure in thecylinder, and. means for communicating said chamber and cylinder portduring relative passage of the cylinder port and valve bridge.

13. In a fluid pressure pump or motor, a rotary barrel having acylinder, a piston in the cylinder, adjustable reactance means toreciprocate the piston, means for adjusting the reactance means,

a valve for the cylinder, said valve having fluid circuit ports forvalving cooperation with the cylinder, bridge means between the ports ofthe valve providing positive overlap in two directions with the cylinderport, means mounting the valve for rotation to different adjustedpositions, and means responsive to changes in delivery pressure of thepump for rotating the valve to different adjusted positions foreffecting predetermined pre-compression and pre-expansion of theoperating fluid in the cylinder during relative passage of the cylinderport and bridge means.

14, In a fluid pressure pump or motor, a casing, a-rotary barrel havinga cylinder, a piston in the cylinder, adjustable reactance means torecipromeans, a valve pintle for the cylinder and rotatable relative tothe casing, said valve pintle having fluid circuit ports for valvingcooperation with the cylinder, bridge means between the ports of thevalve, positive overlap associated with said bridge means at each sideof the center line of the bridge, means mounting the valve for rotationin the casing to different adjusted positions, and meanseassociated withsaid valve and responsive to delivery pressure of the pump for rotatingsaid valve to 'diflerent adjusted positions and in the direction ofrotation of the pump for effecting predetermined compression andexpansion respectively of the working fluid in the individual cylinderduring the time element in which the cylinder passes the bridge and theassociated positive overlap, said time element being determined by theamount of rotation of the valve pintle and the operating pressure of thepump respectively, and being sufficient to compress the segregatedworking fluid of the individual cylinder to the delivery pressurethereby providing communication between the discharge of the individualcylinder and the delivery port of said valve at an equalized pressure.

15'. In a fluid pressure pump or motor the combination of a casing, acylinder barrel having a cylinder, a piston in the cylinder, adjustablereactance means to reciprocate the piston, means for adjusting thereactance means, 'a. rotatably 20 adjustable pintle for the cylinder,said cylinder having a port, said pintle having fluid circuit ports invalving cooperation with the cylinder port, bridge means between theports of the pintle, positive overlaps associated with said bridge meansto control the time element of communication of the cylinder port withthe pintle ports, means mounting the pintle for rotation in the casingto difierent adjusted positions, and means responsive to changes indelivery pressure of the pump for rotating the pintle to differentadjusted positions for effecting predetermined pre-compression andpre-expansion of the working fiuid in the cylinder respectively, duringthe passage of the cylinder port and the said bridge means, and therebyto adjust the pressure in said cylinder to the working pressure of saidpintle ports respectively prior to the communication of the cylinderport with the respective pintle ports.

ELEK BENEDEK. 20

